Reznor SCE Unit Installation Manual - Manual (Page 34)

Form RZ-NA I-SCE, Page 34
31. Cleaning Pilot
and Burners
CAUTION: When
cleaning, wearing eye
protection is
recommended.
29. Vent/Combustion
Air System
32. Spark Ignition
System
Check at least once a year. Inspect all joints, seams and terminal caps. Replace any defective
parts.
30. Burner Rack Burner Rack Removal Instructions
1. Turn off the gas supply.
2. Turn off the electric supply.
3. Remove control access side panel.
4. Disconnect ignition and flame sensor leads.
5. Mark and disconnect electric valve leads.
6. Uncouple the union in the gas supply.
7. Remove sheetmetal screws in the top corners of the burner rack assembly.
8. Pull "drawer-type" burner rack out of the furnace.
To disassemble the burner rack:
1. Remove Carryover System --
Natural Gas - remove the flash carryover system from the "manifold end" of the burner rack
NOTE: Natural gas burner racks manufactured prior to Series 6 may have a lighter tube carryover
system. Break the lighter tube connection at the orifice and remove the supply tubing, the drip
shield and the lighter tube.
Propane Gas - break the lighter tube connection at the regulator and remove the lighter tube
orifice supply tubing; remove the retaining screws in the drip shield and the shield; remove the
retaining screws and slide out the lighter tube.
2. Pull main burners horizontally away from injection opening and lift out.
3. Remove manifold bracket screws and remove manifold.
4. Remove burner orifices.
5. Remove screws and lift out pilot burner.
Follow the instructions in Paragraph 30 to clean. To re-assemble and replace, reverse the above
procedures being careful not to create any unsafe conditions.
In the event the pilot flame is short and/or yellow, check the pilot orifice for blockage caused by
lint or dust accumulation. Remove the pilot orifice and clean with air pressure. DO NOT REAM
THE ORIFICE. Check and clean the aeration slot in the pilot burner.
Clean the metal sensing probe and the pilot hood with an emery cloth and wipe off the ceramic
insulator. Check the spark gap; spark gap should be maintained to .100". After the pilot is cleaned,
blow any dirt away with compressed air.
Clean main burners and burner orifices using air pressure. Use an air nozzle to blow out scale and
dust accumulation from the burner ports. Alternately blow through the burner ports and the
venturi. Use a fine wire to dislodge any stubborn particles from the burner ports. Do not use
anything that might change the port size.
Clean the burner rack carryover systems with air pressure.
The ignition controller provides the high voltage spark to ignite the pilot service and also acts as
the flame safety device. After ignition of the pilot gas, the controller electronically senses the
pilot flame. A separate solid metal probe in the pilot burner assembly is used to sense the flame.
A low voltage DC electrical signal is imposed on the metal probe which is electrically insulated
from ground. Proper operation of the electronic spark ignition system requires a minimum
flame signal of .2 microamps DC as measured by a microampmeter. When the pilot flame
impinges on the sensing probe, the flame acts as a conduction path to ground. This completes
the DC circuit; the ignition controller responds by energizing the main gas valve.
CAUTION: Due to
high voltage on pilot
spark wire and pilot
electrode, do not touch
when energized. See
Hazard Levels, page 2.
If no spark occurs, check the following:
a) Voltage between blue and white terminals (non-lockout type pilot) and Terminals 2 and 5
(lockout type pilot) on the ignition controller should be at least 20 volts and no higher than
32 volts. Refer to Troubleshooting (Paragraph 36) if no voltage is observed.
b) Short to ground in the high tension lead and/or ceramic insulator.
c) Pilot spark gap should be approximately .100". (See FIGURE 35.)
NOTE: When checking for spark with the pilot burner assembly removed from the burner rack,
the pilot assembly must be grounded to the heater for proper spark.
If the above conditions are normal and no spark occurs, replace the ignition controller.